Polyvinyl pyrrole host material, luminescent layer comprising the same, and organic electroluminescent device comprising the luminescent layer

ABSTRACT

Provided are a polyvinyl pyrrole host material emitting highly efficient phosphorescence, a luminescent layer using the material, and an organic electroluminescent display device. The polyvinyl pyrrole host material shows highly efficient luminescence having improved energy transfer, and thus is useful for an organic electroluminescent display device and other various light emitting devices.

CROSS-REFERENCE TO RELATED PATENT APPLICATION AND CLAIM OF PRIORITY

This application claims the benefit of Korean Patent Application No.10-2006-0010920, filed on Feb. 4, 2006 in the Korean IntellectualProperty Office, the disclosure of which is incorporated herein in itsentirety by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a polyvinyl pyrrole host material, aluminescent layer including the same, and an organic electroluminescentdisplay device including the luminescent layer, and more particularly,to a polyvinyl pyrrole host material which has improved energy transfer,a luminescent layer including the same, and an organicelectroluminescent display device including the luminescent layer withimproved efficiency.

2. Description of the Related Art

An organic electroluminescent display device is a self-emissive displaydevice using the principle that when a current is applied to afluorescent or phosphorescent organic compound thin layer, electrons andholes combine in an organic layer and thus light is generated. Theorganic electroluminescent display device is lightweight and has simpleelements, and the manufacturing process thereof is straightforward,providing high, quality images and a wide viewing angle. Also, theorganic electroluminescent display device can provide high color purityand realize perfect mobile images and is operated at a low power and alow driving voltage, which are appropriate properties for mobileelectronic equipment.

Generally, an organic electroluminescent display device includes ananode formed on a substrate, and a hole transporting layer, aluminescent layer, an electron transporting layer, and a cathode aresequentially formed on the anode. The hole transporting layer, theluminescent layer, and the electron transporting layer are organiclayers formed of organic compounds. The above described organicelectroluminescent display device operates as follows. When a voltage isapplied between the anode and the cathode, holes injected from the anodemigrate via the hole transporting layer to the luminescent layer. Theelectrons are injected from the cathode via the electron transportinglayer to the luminescent layer, and carriers are recombined in the areaof the luminescent layer to generate excitons. The excitonsradioactively decay and thus light at a wavelength corresponding to aband gap of the material is emitted.

The material forming the luminescent layer of the organicelectroluminescent display device can be classified into a fluorescentmaterial using singlet excitons and a phosphorescent material usingtriplet excitons according to the light emitting mechanism. Suchfluorescent materials or phosphorescent materials are used by themselvesor doped in an appropriate host material to form a luminescent layer,and as a result of electron excitation, singlet excitons and tripletexcitons are formed in a host. The statistical ratio of the singletexcitons and the triplet excitons is 1:3 (Baldo, et al., Phys. Rev. B,1999, 60, 14422).

When the luminescent layer of the organic electroluminescent displaydevice is formed of a fluorescent material, triplet excitons generatedin the host are wasted, whereas when the luminescent layer is formed ofphosphorescent material, both singlet and triplet excitons can be usedand thus the internal quantum efficiency may reach 100%. Accordingly,when formed of a phosphorescent material, the luminescent layer can havemuch higher luminous efficiency than when formed of a fluorescentmaterial.

Also, the material forming the luminescent layer can be classified intoa luminescent material used alone and a light emitting materialemploying a host/dopant light emitting system. Recently, M. E. Thompsonreported in Chem. Mat. 16,4743 (2004) an excellent result of aderivative including silicon and having a very wide gap energy that isused as a host for a blue light emitting material compared to a lightemitting material used alone.

The light emitting material used alone has problems such as formingexcimers by interaction between molecules and reduction in color purityand efficiency. The host/dopant light emitting system has improved colorpurity compared to the light emitting material used alone and canachieve an increase in efficiency by energy transfer. However, a newhost material with improved energy transfer is still required tomanufacture a high efficiency light emitting device.

SUMMARY OF THE INVENTION

The present invention provides a polyvinyl pyrrole host material withimproved energy transfer.

The present invention also provides a luminescent layer including thepolyvinyl pyrrole host material.

The present invention also provides an organic electroluminescentdisplay device including the luminescent layer.

According to an aspect of the present invention, there is provided apolyvinyl pyrrole host material represented by Formula 1 below:

where R₁, R₂, R₃, and R₄ are each independently a hydrogen, a halogenatom, a carboxyl group, an amino group, a nitro group, a cyano group, asubstituted or unsubstituted C₁-C₂₀ alkyl group, a substituted orunsubstituted C₁-C₂₀ alkoxy group, a substituted or unsubstituted C₂-C₂₀alkenyl group, a substituted or unsubstituted C₂-C₂₀ alkynyl group, asubstituted or unsubstituted C₁-C₂₀ heteroalkyl group, a substituted orunsubstituted C₆-C₃₀ aryl group, a substituted or unsubstituted C₇-C₃₀arylalkyl group, a substituted or unsubstituted C₅-C₃₀ heteroaryl group,or a substituted or unsubstituted C₃-C₃₀ heteroarylalkyl group, and twoof these can be fused to form a fusion ring of 5 to 7 circles, and n isan integer from 10 to 10,000.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the present invention, and many of theabove and other features and advantages of the present invention, willbe readily apparent as the same becomes better understood by referenceto the following detailed description when considered in conjunctionwith the accompanying drawings in which like reference symbols indicatethe same or similar components, wherein:

FIGS. 1A through 1F schematically illustrate a stack structure of anorganic electroluminescent display device according to an embodiment ofthe present invention;

FIG. 2 is a schematic view of an organic electroluminescent displaydevice manufactured according to an embodiment of the present invention;

FIG. 3 illustrates an absorption spectrum and a PL spectrum of apolyvinyl pyrrole host obtained from Example 3; and

FIG. 4 illustrates an absorption spectrum and a PL spectrum of apolyvinyl pyrrole host obtained from Example 5.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will now be described more fully with reference tothe accompanying drawings, in which exemplary embodiments of theinvention are shown.

The present invention provides a polyvinyl pyrrole host materialrepresented by Formula 1 below which facilitates energy transfer in thelight emitting mechanism of a host/dopant light emitting system by beingused in combination with a dopant, thereby improving the luminousefficiency.

where R₁, R₂, R₃, and R₄ are each independently a hydrogen, a halogenatom, a carboxyl group, an amino group, a nitro group, a cyano group, asubstituted or unsubstituted C₁-C₂₀ alkyl group, a substituted orunsubstituted C₁-C₂₀ alkoxy group, a substituted or unsubstituted C₂-C₂₀alkenyl group, a substituted or unsubstituted C₁-C₂₀ alkynyl group, asubstituted or unsubstituted C₁-C₂₀ heteroalkyl group, a substituted orunsubstituted C₆-C₃₀ aryl group, a substituted or unsubstituted C₇-C₃₀arylalkyl group, a substituted or unsubstituted C₅-C₃₀ heteroaryl group,or a substituted or unsubstituted C₃-C₃₀ heteroarylalkyl group. Two ofthese can be fused to form a fusion ring of 5 to 7 circles.

N is an integer from 10 to 10,000.

Generally, energy is efficiently transferred when the singlet energylevel S^(H) ₀ of the host is lower than the singlet energy level S^(D) ₀of the dopant, and the triplet energy level T^(H) ₁ of the host ishigher than the triplet energy level T^(D) ₁ of the dopant. Also,preferably, the light emitting area of the host material overlaps withthe absorption area of the dopant material, and the host material andthe dopant material do not create condensation and have high thermalstability.

The above described polyvinyl pyrrole host material represented byFormula 1 has an improved luminous efficiency due to good miscibilitybetween molecules and a good coating characteristic when emitting lightunder the light emitting mechanism under the above-described host/dopantlight emitting system.

According to an embodiment of the present invention, the compound ofFormula 1 may be a polymer where a hydrogen atom present in the pyrrolein the center of the polymer is substituted with a substituted orunsubstituted phenyl group, as represented in Formula 2 or 3 below.

where R₁, R₂, and R₃ are at least one substitution groups on the rings,and are each independently a halogen atom, a carboxyl group, an aminogroup, a nitro group, a cyano group, a substituted or unsubstitutedC₁-C₂₀ alkyl group, a substituted or unsubstituted C₁-C₂₀ alkoxy group,a substituted or unsubstituted C₂-C₂₀ alkenyl group, a substituted orunsubstituted C₂-C₂₀ alkynyl group, a substituted or unsubstitutedC₁-C₂₀ heteroalkyl group, a substituted or unsubstituted C₆-C₃₀ arylgroup, a substituted or unsubstituted C₇-C₃₀ aryl alkyl group, asubstituted or unsubstituted C₅-C₃₀ heteroaryl group, or a substitutedor unsubstituted C₃-C₃₀ heteroarylalkyl group, and

R₄ is a halogen atom, a carboxyl group, an amino group, a nitro group, acyano group, a substituted or unsubstituted C₁-C₂₀ alkyl group, asubstituted or unsubstituted C₁-C₂₀ alkoxy group, a substituted orunsubstituted C₂-C₂₀ alkenyl group, a substituted or unsubstitutedC₂-C₂₀ alkynyl group, a substituted or unsubstituted C₁-C₂₀ heteroalkylgroup, a substituted or unsubstituted C₆-C₃₀ aryl group, a substitutedor unsubstituted C₇-C₃₀ arylalkyl group, a substituted or unsubstitutedC₅-C₃₀ heteroaryl group, or a substituted or unsubstituted C₃-C₃₀heteroarylalkyl group, and

n is an integer from 10 to 10,000.

According to an embodiment of the present invention, the compoundaccording to Formula 1 can be a polymer where a hydrogen atom in pyrrolein the center of the polymer is substituted with a substituted orunsubstituted anthracenyl group, as represented in Formulas 4 through 6.

where R₁, R₂, R₃, and R₄ are at least one substitution groups on therings, and are each independently a hydrogen, a halogen atom, a carboxylgroup, an amino group, a nitro group, a cyano group, a substituted or aunsubstituted C₁-C₂₀ alkyl group, a substituted or unsubstituted C₁-C₂₀alkoxy group, a substituted or unsubstituted C₂-C₂₀ alkenyl group, asubstituted or unsubstituted C₂-C₂₀ alkynyl group, a substituted orunsubstituted C₁-C₂₀ heteroalkyl group, a substituted or unsubstitutedC₆-C₃₀ aryl group, a substituted or unsubstituted C₇-C₃₀ arylalkylgroup, a substituted or unsubstituted C₅-C₃₀ heteroaryl group, or asubstituted or unsubstituted C₃-C₃₀ heteroarylalkyl group, and

n is an integer from 10 to 10,000.

According to an embodiment of the present invention, the compoundaccording to Formula 1 can be a polymer where two or more hydrogen atomsin pyrrole in the center of the polymer are substituted with a fusionring, as represented in Formulas 8 through 10.

where R₁, R₂, and R₃ are at least one substitution groups on the rings,and are each independently a halogen atom, a carboxyl group, an aminogroup, a nitro group, a cyano group, a substituted or unsubstitutedC₁-C₂₀ alkyl group, a substituted or unsubstituted C₁-C₂₀ alkoxy group,a substituted or unsubstituted C₂-C₂₀ alkenyl group, a substituted orunsubstituted C₂-C₂₀ alkynyl group, a substituted or unsubstitutedC₂-C₂₀ heteroalkyl group, a substituted or unsubstituted C₆-C₃₀ arylgroup, a substituted or unsubstituted C₇-C₃₀ arylalkyl group, asubstituted or unsubstituted C₅-C₃₀ heteroaryl group, or a substitutedor unsubstituted C₃-C₃₀ heteroarylalkyl group, and

n is an integer from 10 to 10,000.

According to an embodiment of the present invention, compound accordingto Formula 1 above can be a polymer where a hydrogen atom in pyrrole inthe center of the polymer is substituted with a carbazolyl group, asrepresented by Formulas 11 and 12.

where R₁, R₂, and R₃ are at least one substitution groups on the rings,and are each independently a halogen atom, a carboxyl group, an aminogroup, a nitro group, a cyano group, a substituted or unsubstitutedC₁-C₂₀ alkyl group, a substituted or unsubstituted C₁-C₂₀ alkoxy group,a substituted or unsubstituted C₂-C₂₀ alkenyl group, a substituted orunsubstituted C₂-C₂₀ alkynyl group, a substituted or unsubstitutedC₁-C₂₀ heteroalkyl group, a substituted or unsubstituted C₆-C₃₀ arylgroup, a substituted or unsubstituted C₇-C₃₀ aryl alkyl group, asubstituted or unsubstituted C₅-C₃₀ heteroaryl group, or a substitutedor unsubstituted C₃-C₃₀ heteroarylalkyl group, and

R₄ is a halogen atom, a carboxyl group, an amino group, a nitro group, acyano group, a substituted or unsubstituted C₁-C₂₀ alkyl group, asubstituted or unsubstituted C₁-C₂₀ alkoxy group, a substituted orunsubstituted C₂-C₂₀ alkenyl group, a substituted or unsubstitutedC₂-C₂₀ alkynyl group, a substituted or unsubstituted C₁-C₂₀ heteroalkylgroup, a substituted or unsubstituted C₆-C₃₀ aryl group, a substitutedor unsubstituted C₇-C₃₀ arylalkyl group, a substituted or unsubstitutedC₅-C₃₀ heteroaryl group, or a substituted or unsubstituted C₃-C₃₀heteroarylalkyl group, and

n is an integer from 10 to 10,000.

According to an embodiment of the present invention, the compound ofFormula 1 may be preferably the compound of Formula 13 or 14 below.

wherein n is an integer from 10 to 10,000.

wherein n is an integer from 10 to 10,000.

The above described polyvinyl pyrrole host material as in Formula 1, forexample, the polyvinyl host material of Formulas 2 through 14 showimproved luminous efficiency by improved energy transfer and thus can beused in the luminescent layer of various light emitting devices, andparticularly can be used as a luminescent layer in an organicelectroluminescent display device.

When the polyvinyl pyrrole host material of Formula 1 according to anembodiment of the present invention is employed in the luminescentlayer, the amount of the polyvinyl pyrrole material may be 70-99% byweight of the total amount of the light emitting material in theluminescent layer. If the amount is less than 70% by weight, tripletexcitons are quenched, thus decreasing efficiency. If the amount isgreater than 99% by weight, the light emitting material becomesinsufficient and thus the efficiency and life span decrease.

As described above, the polyvinyl pyrrole host material of Formula 1according to an embodiment of the present invention can be employed witha dopant material to form a host/dopant light emitting system.

Examples of the dopant materials include a phosphorescent dopant, forexample, an iridium based complex such as bisthienylpyridineacetylacetonate Iridium, bis(benzothienylpyridine)acetylacetonateIridium, bis(2-phenylbenzothiazole)acetylacetonate Iridium,bis(1-phenylisoquinoline)Iridium acetylacetonate,tris(1-phenylisoquinoline)Iridium or tris(2-phenylpyridine)Iridium(Ir(ppy)₃), or an europium complex such astris(theotyltrifluoroacetonate)europium (Eu(TTA)₃),(1,10-phenanthroline)-tris(4,4,4-trifluoro-1-(2-thienyl)butane-1,3-dionate)europium(Eu(TTA)₃phen), tris(dibenzoylmethanato)phenanthroline europium(Eu(DBM)₃(Phen)), or (4,7-diphenylphenanthroline)-tris(4,4,4,-trifluoro)-1-(2-thienyl)-butane-1,3-dionateeuropium (Eu(TTA)₃bath), tris(4-methylbenzoate lanthanide) (La(MeB)₃),or tris(4-methoxy benzoyl benzoate)lanthanide (La(MeOBB)₃). Also,tris(4,7-diphenyl-1,10-phenanthroline)ruthenium(II)perchlorate,tris(hexafluoroacetylacetonate) mono(1,10-phenanthroline)erbium(III),bis(2-methyl-8-hydroxy quinolinato)zinc,1,4-bis[9-ethyl-3-carbazovinylene)-2-methoxy-5-(2-ethylhexyloxy)benzene,1-(2,2-diphenylethen-1-yl)pyrene, tris(8-hydroxyquinolato)aluminum, and4,4′-bis[4-(di-p-tolylamino)styryl]biphenyl can be used.

The amount of the dopant may be approximately 1 to 30% by weight of thetotal amount of the light emitting material. If the amount of the dopantis less than 1% by weight, the luminous efficiency may decrease, and ifthe amount is greater than 30%, the amount of the host material maydecrease which decreases the luminous efficiency.

The luminescent layer including the polyvinyl pyrrole host material ofFormula 1 may further include one or more materials selected from thegroup consisting of a polymer host, a mixed host of polymer and a smallmolecule, small molecule host, and a non-light emitting polymer matrix.Here, an ordinary polymer host, a small molecule host, and a non-lightemitting polymer matrix used for forming a luminescent layer of anorganic electroluminescent display device can be used. Examples of thepolymer host materials are PVK and PF, and examples of the smallmolecule host include CBPs (4,4′-N,N′-CBP), 4,4′-bis[9-s(3,6-biphenylcarbazolyl)]-1-1,1′-biphenyls(4,4′-bis[9-s]-1-1,1′-biphenyls,9,10-bis[(2′,7′-tertial-butyl)-9′,9″-spirobifluorenyl anthracene,tetrafluorene, and examples of the non-light emitting polymer matrixinclude polymethyl methacrylate, polystyrene, etc., but is not limitedthereto.

The luminescent layer including the polyvinyl pyrrole host material ofFormula 1 according to an embodiment of the present invention can beapplied to various light emitting devices and may be appliedparticularly to an organic electroluminescent display device.

The organic electroluminescent display device according to an embodimentof the present invention includes a luminescent layer which is formedusing a polyvinyl pyrrole host material represented by Formula 1. Thepolyvinyl pyrrole host material represented by Formula 1 is very usefulas a phosphorescent host material and, though depending on the dopant,shows good luminescence in the blue wavelength region.

FIGS. 1A through 1F illustrate a stack structure of an organicelectroluminescent display device according to embodiments of thepresent invention.

Referring to FIG. 1A, a luminescent layer 12 including the polyvinylpyrrole host of Formula 1 is stacked on a first electrode 10 and asecond electrode 14 is formed on the luminescent layer 12.

In FIG. 1B, a luminescent layer 12 including the polyvinyl pyrrole hostof Formula 1 is stacked on a first electrode 10 and a hole blockinglayer (HBL) 13 is formed on the luminescent layer 12, and a secondelectrode 14 is formed on the hole blocking layer (HBL) 13.

In the organic electroluminescent display device in FIG. 1C, a holeinjection layer 11 is disposed between the first electrode 10 and theluminescent layer 12 including the polyvinyl pyrrole host.

The organic electroluminescent display device of FIG. 10 has the samestack structure as in FIG. 10, except that an electron transportinglayer (ETL) 15 is formed instead of an HBL 13 formed on the luminescentlayer 12 including the polyvinyl pyrrole host of Formula 1.

The organic electroluminescent display device in FIG. 1E has the samestack structure as in FIG. 10 except that a two-layered stack formed ofan HBL 13 and an electron transporting layer 15 is used instead of theHBL 13 formed on the luminescent layer 12 including the polyvinylpyrrole host of Formula 1. In some cases, an electron injection layermay be further disposed between the electron transporting layer 15 andthe second electrode 14 in the organic electroluminescent display devicein FIG. 1E.

The organic electroluminescent display device in FIG. 1F has the samestructure as in FIG. 1E, except that a hole transporting layer 16 isfurther included between the hole injection layer 11 and the luminescentlayer 12 including the polyvinyl pyrrole host of Formula 1. The holetransporting layer 16 blocks injection of impurities from the holeinjection layer 11 to the luminescent layer 12.

The organic electroluminescent display device having the above describedstack structure can be formed in the conventional manner and the methodof manufacturing thereof is not limited.

The thickness of the luminescent layer may be 30 to 100 nm. If thethickness of the luminescent layer is less than 30 nm, the efficiencyand life span of the organic electroluminescent display device decrease.If the thickness of the luminescent layer is over 100 nm, the drivingvoltage increases.

The luminescent layer including the polyvinyl pyrrole host of Formula 1may also function as an electron transporting layer or a holetransporting layer.

A buffer layer may be formed between the electrode and the luminescentlayer, between the electrode and the electron transporting layer, orbetween the electrode and the hole transporting layer. The buffer layercan be formed of a conventionally used material, and examples of thebuffer layer include, but are not limited to, copper phthalocyanine,polythiophene, polyaniline, polyacetylene, polypyrrole, polyphenylenevinylene, and derivatives thereof.

The material of the hole transporting layer 16 may be a conventionallyused material such as aryl amine-based material, preferablycarbazole-based material, but are not limited thereto. Thecarbazole-based material may be one or more selected from the groupconsisting of 1,3,5-triscarbazolylbenzene, 4,4′-biscarbazolylbiphenyl(CBP), polyvinylcarbazole, m-biscarbazolylphenyl,4,4′-biscarbazolyl-2,2′-dimethylbiphenyl (dmCBP),4,4′,4″-tri(N-carbazolyl)triphenylamine,1,3,5-tris(2-carbazolylphenyl)benzene,1,3,5-tris(2-carbazolyl-5-methoxyphenyl)benzene, andbi(4-carbazolylphenyl)silane.

The electron transporting layer can be formed of a conventionally usedmaterial, and preferable examples of the material include one or morecompounds selected from the group consisting of an organic metal complexincluding a metal and an organic ligand, an oxadiazole based compound, aphenanthroline compound, a triazine compound, and a triazole compound.

An unlimited example of the organic metal complex may be one or morematerials selected from the group consisting ofbis(8-hydroxyquinolato)biphenoxy metal, bis(8-hydroxyquinolato)phenoxymetal, metal(bis(2-methyl-8-hydroxyquinolato)biphenoxy metal),(bis(2-methyl-8-hydroxyquinolato)phenoxy metal),bis(2-methyl-8-quinolinolato)(para-phenyl-phenolato)metal), and(bis(2-(2-hydroxyphenyl)quinolato)metal), and the metal is aluminum,zinc, beryllium, and gallium.

The electron transporting material may bebis(8-hydroxyquinolato)biphenoxy aluminum,bis(8-hydroxyquinolato)phenoxy aluminum,bis(2-methyl-8-hydroxyquinolato)biphenoxy aluminum,bis(2-methyl-8-hydroxyquinolato)phenoxy aluminum,bis(2-methyl-8-quinolinolato)(para-phenyl-phenolato)aluminum(BAlq), orbis(2-(2-hydroxy phenyl)quinolato)zinc.

The spirofluorene compound has two connection rings between the twospirofluorenes and the connection can be substituted with triazole,oxadiazole, naphthalene, anthracene, or phenyl, and the no. 9 positionof each fluorene may be substituted with O, S, Se, N—R, or P—R, or N—Ror P—R may connect two spirofluorenes to each other. R is respectively Hor a substitution group selected from the group consisting of a C₁-C₂₀alkyl group, a C₅-C₂₀ aryl group having a C₁-C₂₀ alkyl group, a C₂-C₂₀heteroaryl group, and a C₆-C₂₀ aryl group having a C₁-C₂₀ alkoxy group.The spirofluorene compound is preferably 2,5-dispirobifluorene-1,3,4-oxadiazole.

Examples of the oxadiazole based compound are(4-biphenylyl)-5-(4-tert-butyl phenyl)-1,3,4-oxadiazole, etc., andexamples of the phenanthroline compound are2,9-dimethyl-4,7-diphenyl-9,10-phenanthroline (BCP), etc. Examples ofthe triazine compound include 2,4,6-tris(diphenylamino)-1,3,5-triazine,2,4,6-tricarbazole, 1,3,5-triazine,2,4,6-tris(N-phenyl-2-naphthylamino)-1,3,5-triazine,2,4,6-tris(N-phenyl-1-naphthylamino)-1,3,5-triazine, etc. Examples ofthe triazole compound include3-phenyl-4-(1′-naphthyl)-5-phenyl-1,2,4-triazole, etc.

Examples of the HBL include conventionally used materials, and may bepreferably LiF, BaF₂ or MgF₂, but are not limited thereto.

In order to increase the efficiency and the lifespan of the organicelectroluminescent display device, the layers may be formed of a mixedmaterial or layers having additional functions may be introduced. Inaddition, the number of the layers may be reduced using a materialhaving multiple functions in order to simplify the manufacturing of thedevice.

The organic electroluminescent display device according to an embodimentof the present invention does not require any particular apparatus ormethod, and can be manufactured by a method of manufacturing an organicelectroluminescent display device using a conventional light emittingmaterial.

Light emitting diodes using the host materials as described above can beused in full color display light source illumination, a backlight, anoutdoor bulletin board, optical communications, or interior design.

Hereinafter, the present invention will be described in detail withreference to the following examples. The following examples are forillustrative purposes only and are not intended to limit the scope ofthe invention.

EXAMPLE 1 Synthesis of poly(1-vinyl indole)

As represented by Equation 1, indole was vinylated with acetylene atabout 95-97° C. for 7 hours in a base system using KOH-DMSO (dimethylsulfoxide) as represented in Equation 1 to obtain 1-vinyl indole as atransparent fluid colorless liquid at a yield of 43%.

As represented in Equation 2, 1-vinyl indole obtained from Equation 1was radically polymerized with azobisisobutylonitryl (AIBN) at 60° C.for 72 hours to obtain poly(1-vinyl indole) having a molecular weight of3,800 as white powder at a yield of 75%.

EXAMPLE 2 Synthesis of poly(1,4-bis[2-(1-vinyl)pyrrolypenzene)

As represented in Equation 3, hydroxyl amine hydrochloride and1,4-diacetylenebenzene were reacted in a pyridine (py) solvent at 80° C.for 2 hours to obtain 1,4-diacetylbenzene oxime as white powder at ayield of 95%.

As represented in Equation 4, acetylene and 1,4-diacetylbenzene dioxime1,2-bis-[2-(1-vinyl)pyrrolyl]benzene was obtained as a white crystal ata yield of 15% in KOH-DMSO base system.

The obtained 1,4-bis-[2-(1-vinyl)pyrrolyl]benzene was radicallypolymerized in the presence of AIBN at 70° C. for 165 hours to obtainpoly(1,4-bis[2-(1-vinyl)pyrrolyl]benzene) having a molecular weight of1100 at a yield of 33%.

EXAMPLE 3 Synthesis of poly(1-vinyl-4,5-dihydrobenzo[g]indole)

Hydroxyl amine and 1-tetrarone were reacted at 70° C. for 2 hours inDMSO, and then reacted with acetylene in a KOH-DMSO base system tomanufacture 4,5-dihydrobenzo[g]indole and1-vinyl-4,5-dihydrobenzo[g]indole at a yield of 45% and 21%,respectively.

As represented in Equation 6, 1-vinyl-4,5-dihydrobenzo[g]indole wasradically polymerized at 80° C. for 72 hours in the presence of AIBN tosynthesize poly(1-vinyl-4,5-dihydrobenzo[g]indole) with a molecularweight of 1,500 as light brown powder at a yield of 5%.

EXAMPLE 4 Synthesis of poly(1-vinyl-2,5-diphenylpyrrole)

As represented in Equation 7, 2,5-diphenyl pyrrole at a yield of 17% wassynthesized by Trofimov reaction of 1-phenyl ethanone oxime in KOH/DMSObase system in the presence of ethynyl-benzene at 160° C. for 6 hours.

As represented in Equation 8, 2,5-diphenyl pyrrole was reacted withacetylene at 150° C. for 3 hours in a KOH/DMSO base system tomanufacture 1-vinyl-2,5-diphenyl pyrrole at a yield of 75%.

The obtained 1-vinyl-2,5-diphenyl pyrrole was pressurized and radicallypolymerized at 65° C. for 15 hours in the presence of AIBN tomanufacture poly(1-vinyl-2,5-diphenyl pyrrole) having a molecular weightof 2,300 at a yield of 37%.

EXAMPLE 5 Synthesis of poly(9-methyl-3-(1-vinylpyrrole-2-il)carbazole)

As represented in Equation 9, carbazole was reacted with methyl iodideat 20° C. for 5 hours in a KOH/DMSO base system to synthesize 9-methylcarbazole at a yield of 95%.

As represented in Equation 10, 9-methyl carbazole was reacted withMeCOCl at 10° C. for 7 hours in the presence of CHCl₃ and AlCl₃ tomanufacture 1-(9-methyl carbazole-3-il)ethanone at a yield of 45%.

As represented by Equation 11, 1-(9-methyl carbazole-3-il)ethanoneobtained from Equation 10 was reacted with NH₂OH.HCl at 20-70° C. for 3hours in a NaOH/EtOH base system to synthesize 1-(9-methylcarbazole-3-il)ethanone oxime at a yield of 90%.

As represented in Equation 12, 9-methyl-3-(a-vinylpyrrole-2-il)carbazole was manufactured at a yield of 56% by Trofiamovreaction of 1-(9-methyl carbazole-3-il)ethanone oxime obtained fromEquation 11 with acetylene at 30 atmosphere of pressure, at 100° C., andfor 2 hours in a KOH/DMSO base system.

The obtained 9-methyl-3-(1-vinyl pyrrole-2-il)carbazole was radicallypolymerized in the presence of AIBN at 65° C. for 18 hours tomanufacture poly[9-methyl-3-(1-vinyl pyrrole-2-il)carbazole] having amolecular weight of 3,200 at a yield of 33%.

EXAMPLE 6 Synthesis of poly(1-vinyl-2-(1-anthracenyl)pyrrole) and1-vinyl-2-(2-anthracenyl)pyrrole

As represented in Equation 13, anthracene was reacted with MeCOCl at0-5° C. for 2.5 hours in the presence of benzene and AlCl₃ to synthesize9-acetyl anthracene at a yield of 40%.

As represented by Equation 14, 9-acetyl anthracene was reacted in thepresence of AlCl₃ and benzene-nitrobenzene at 40° C. for 5 hours tosynthesize 1-acetyl anthracene and 2-acetyle anthracene at a yield of10%.

The obtained 1-acetyl anthracene and 2-acetyl anthracene wererespectively reacted with NH₂OH.HCl at 35-50° C. for 5 hours in aNaOH/EtOH base system to synthesize 1-anthracene-1-il-ethanone oxime and2-anthracene-2-il-ethanone oxime at a yield of 37% and 42%.

2-anthracene-1-il-1-vinyl-1H-pyrrole and 2-anthracene-2-il-1-vinyl-1H-pyrrole were manufactured at a yield of 42% and 33%, respectively, byTrofiamov reaction of the obtained 1-anthracene-1-il-ethanone oxime and2-anthracene-2-il-ethanone oxime with acetylene at 30 atmosphere ofpressure, at 100° C. and for 3 hours in a KOH/DMSO base system.

The obtained 2-anthracene-1-il-1-vinyl-1H-pyrrole and2-anthracene-2-il-1-vinyl-1H-pyrrole were pressurized and radicallypolymerized at 65° C. for 15 hours in the presence of AIBN tomanufacture poly(1-vinyl-2-(1-anthracene)pyrrole) and1-vinyl-2-(2-anthracenenil)pyrrole having a molecular weight of 3,500respectively at a yield of 33% and 42%.

EXPERIMENTAL EXAMPLE 1 Photoluminescence

Photoluminescence of poly(1-vinyl-4,5-dihydrobenzo[g]indole) of Formula13 and poly(9-methyl-3-(1-vinyl pyrrole-2-il)carbazole) of Formula 14obtained in the above described manner was measured in the followingmanner: the above compounds were dissolved in methylene chloride andthus were made as 10⁻⁴ M solution, and then the photoluminescence of thecompounds in the state of solution was measured. Also, the compoundswere spin-coated and the photoluminescence of the compounds in the formof a film was measured and the result thereof is illustrated in FIGS. 3and 4.

where n is an integer from 10 to 10,000.

where n is an integer from 10 to 10,000.

It is evident from FIGS. 3 and 4 that the polyvinyl pyrrole hostmaterial according to an embodiment of the present invention has goodphosphorescence and thus is appropriate as a phosphorescent materialemitting light in the blue color region.

EXPERIMENTAL EXAMPLE 2 Measurement of Solubility

1% by weight of poly(1-vinyl indole) obtained from Experimental example1 was put into various solvents to measure the solubility. The solventsmay be toluene, CB, 1,4-dioxane, THF, o-xylene, diacetone, alcohol,PGMEA, DMF, DMSO, MeOH, chloroform, and benzene.

Also, the solubility of poly-1,4-bis-[2-(1-vinyl)-pyrrolyl]benzene withthe above solvents was measured.

For example, 40 mg of poly(1-vinyl indole) was put into 4 ml of benzeneand agitated at a normal temperature for 1 hour. Agitation was performedfor 15 hours, a small amount of sediment was precipitated and thesolution became clear. 1 ml (837 mg) of the transparent solution wastaken to another container, and the rest of the film after benzene wasevaporated, was dried at 70° C. in a vacuum of 2 mm Hg until the filmgains a predetermined weight. As a result, the weight of the dried filmwas 6.3 mg. The solubility of poly(1-vinyl indole) to benzene was 0.75%,and the unmelting portion was about 0.25%.

Also, 30 mg of poly-1,4-bis-[2-(1-vinyl)-pyrrolyl]benzene was put into 3ml of benzene and agitated at a normal temperature for 1 hour. Agitationwas performed for 15 hours, a small amount of sediment was precipitatedand the solution became clear. 1 ml (860 mg) of the transparent solutionwas taken to another container, and the rest of the film after benzenewas evaporated, was dried at 70° C. in a vacuum of 2 mm Hg until thefilm gains a predetermined weight. As a result, the weight of the driedfilm was 7.75 mg. The solubility ofpoly-1,4-bis-[2-(1-vinyl)-pyrrolyl]benzene to benzene was 0.90%, and theunmelting portion was about 0.10%.

As evident from the solubility measurement result, the polyvinyl pyrrolehost material according to an embodiment of the present invention can bedissolved in various solvents and can be applied to the substrate usingvarious coating methods.

Fabrication of Organic Electroluminescent Display Devices

EXAMPLE 7

A transparent electrode substrate coated with indium-tin oxide (ITO) wascleansed thoroughly, and ITO was patterned using a photoresist resin andan etchant to form an ITO electrode pattern and was cleansed again.Then, PEDOT (poly(3,4-ethylenedioxythiophene)) [Al 4083] was coated onthe resultant material to a thickness of 50 nm and baked at 120° C. forabout 5 minutes to form a hole injection layer.

A composition for forming a luminescent layer, which is obtained bymixing 5 mg of dopant of Formula 15 and 95 mg ofpoly(1-vinyl-4,5-dihydrobenzo[g]indole) of Formula 13 to 10 g ofm-xylene solution was spin coated on the upper portion of the holeinjection layer and was baked at 100° C. for 1 hour, and then thesolvent was removed completely to form a luminescent layer to athickness of 50 nm [5% by weight of the dopant of Formula 15, 95% byweight of the compound of Formula 13].

where n is an integer from 10 to 10,000.

Next, an electron transporting layer to a thickness of 10 nm was formedon the polymer luminescent layer by vacuum-evaporating Alq3 using avacuum evaporator, maintaining a vacuum degree of 4×10⁻⁶ torr or less.Then, LiF was vacuum-evaporated at a speed of 0.1 Å/sec to form anelectron injection layer to a thickness of 1 nm.

Then, Al was deposited at a speed of 10 Å/sec and an anode to athickness of 250 nm was deposited and encapsulated to complete anorganic electroluminescent display device. The encapsulation wasperformed so that BaO powder was put in a glove box under dry nitrogengas and encapsulated with a metal can and finally treated with UVhardener.

The organic electroluminescent display device is a multi-layer deviceand is schematically illustrated in FIG. 2, and the light emittingsurface thereof is 6 mm².

EXAMPLE 8

An organic electroluminescent display device was manufactured in thesame manner as Example 7, except that the luminescent layer in Example 7contains 90% by weight of poly(1-vinyl-4,5-dihydrobenzo[g]indole) ofFormula 13 and 10% by weight of the compound of Formula 15.

EXAMPLE 9

An organic electroluminescent display device was manufactured in thesame manner as Example 7, except that poly(9-methyl-3-(1-vinylpyrrole-2-il)carbazole) of Formula 14 was used in the luminescent layerof Example 7 instead of poly(1-vinyl-4,5-dihydrobenzo[g]indole) ofFormula 13.

EXAMPLE 10

An organic electroluminescent display device was manufactured in thesame manner as Example 9, except that the luminescent layer in Example 9contains 90% by weight of poly(9-methyl-3-(1-vinylpyrrole-2-il)carbazole) of Formula 14 and 10% by weight of the compoundof Formula 15.

CIE (color coordinate), current efficiency, and driving voltage of eachorganic electroluminescent display device obtained from Examples 7through 10 are illustrated in Table 1.

TABLE 1 CIE Current density Driving voltage/ (x, y) (Cd/A @ V) Op · V @100 cd/m² Example 7 (0.15, 0.19) 2.5 @ 7.2 2.8/5.0 Example 8 (0.16,0.21) 3.0 @ 7.0 3.0/5.0 Example 9 (0.15, 0.21) 2.5 @ 7.6 3.0/5.8 Example10 (0.16, 0.23) 3.8 @ 7.2 3.2/5.4

As evident from Table 1, each organic electroluminescent display deviceof Examples 7 through 10 employing the polyvinyl pyrrole host materialaccording to an embodiment of the present invention shows greatbrightness in the blue light emitting region, can be driven at a lowvoltage, and has great current density at a low voltage.

The polyvinyl pyrrole host material according to an embodiment of thepresent invention can efficiently emit blue light and can be used toform a luminescent layer of an organic electroluminescent displaydevice.

While the present invention has been particularly shown and describedwith reference to exemplary embodiments thereof, it will be understoodby those of ordinary skill in the art that various changes in form anddetails may be made therein without departing from the spirit and scopeof the present invention as defined by the following claims.

1. (canceled)
 2. An organic electroluminescence device, comprising: afirst electrode; a second electrode; and a luminescent layer interposedbetween the first electrode and the second electrode, the luminescentlayer comprising: a dopant; and a host material doped with the dopant,the host material represented by Formula 2 or 3:

where R₁, R₂, and R₃ are each independently a halogen atom, a carboxylgroup, an amino group, a nitro group, a cyano group, a substituted orunsubstituted C₁-C₂₀ alkyl group, a substituted or unsubstituted C₁-C₂₀alkoxy group, a substituted or unsubstituted C₂-C₂₀ alkenyl group, asubstituted or unsubstituted C₂-C₂₀ alkynyl group, a substituted orunsubstituted C₁-C₂₀ heteroalkyl group, a substituted or unsubstitutedC₆-C₃₀ aryl group, a substituted or unsubstituted C₇-C₃₀ aryl alkylgroup, a substituted or unsubstituted C₅-C₃₀ heteroaryl group, or asubstituted or unsubstituted C₃-C₃₀ heteroarylalkyl group; R₄ is ahalogen atom, a carboxyl group, an amino group, a nitro group, a cyanogroup, a substituted or unsubstituted C₁-C₂₀ alkyl group, a substitutedor unsubstituted C₁-C₂₀ alkoxy group, a substituted or unsubstitutedC₂-C₂₀ alkenyl group, a substituted or unsubstituted C₂-C₂₀ alkynylgroup, a substituted or unsubstituted C₁-C₂₀ heteroalkyl group, asubstituted or unsubstituted C₆-C₃₀ aryl group, a substituted orunsubstituted C₇-C₃₀ arylalkyl group, a substituted or unsubstitutedC₅-C₃₀ heteroaryl group, or a substituted or unsubstituted C₃-C₃₀heteroarylalkyl group; and n is an integer from 10 to 10,000.
 3. Anorganic electroluminescence device, comprising: a first electrode; asecond electrode; and a luminescent layer interposed between the firstelectrode and the second electrode, the luminescent layer comprising: adopant; and a host material doped with the dopant, the host materialrepresented by Formulas 4 through 6:

where R₁, R₂, R₃, and R₄ are each independently a hydrogen, a halogenatom, a carboxyl group, an amino group, a nitro group, a cyano group, asubstituted or unsubstituted C₁-C₂₀ alkyl group, a substituted orunsubstituted C₁-C₂₀ alkoxy group, a substituted or unsubstituted C₂-C₂₀alkenyl group, a substituted or unsubstituted C₂-C₂₀ alkynyl group, asubstituted or unsubstituted C₁-C₂₀ heteroalkyl group, a substituted orunsubstituted C₆-C₃₀ aryl group, a substituted or unsubstituted C₇-C₃₀arylalkyl group, a substituted or unsubstituted C₅-C₃₀ heteroaryl group,or a substituted or unsubstituted C₃-C₃₀ heteroarylalkyl group; and n isan integer from 10 to 10,000.
 4. An organic electroluminescence device,comprising: a first electrode; a second electrode; and a luminescentlayer interposed between the first electrode and the second electrode,the luminescent layer comprising: a dopant; and a host material dopedwith the dopant, the host material represented by Formulas 8 through 10:

where R₁, R₂, and R₃ are each independently a halogen atom, a carboxylgroup, an amino group, a nitro group, a cyano group, a substituted orunsubstituted C₁-C₂₀ alkyl group, a substituted or unsubstituted C₁-C₂₀alkoxy group, a substituted or unsubstituted C₂-C₂₀ alkenyl group, asubstituted or unsubstituted C₂-C₂₀ alkynyl group, a substituted orunsubstituted C₁-C₂₀ heteroalkyl group, a substituted or unsubstitutedC₆-C₃₀ aryl group, a substituted or unsubstituted C₇-C₃₀ aryl alkylgroup, a substituted or unsubstituted C₅-C₃₀ heteroaryl group, or asubstituted or unsubstituted C₃-C₃₀ heteroarylalkyl group; and n is aninteger from 10 to 10,000. 5-20. (canceled)